\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 2/0/B, 2.5/2/C, 1.5/3/D}
    \tkzDrawPolygon(A,B,C,D)
    \tkzLabelPoints[below](A,B)
    \tkzLabelPoints[right](C)
    \tkzLabelPoints[above](D)

    % 1
    \tkzDrawSegments[dashed](D,B)

    % 2
    \tkzDrawLine[add=0 and 0.8](A,B)
    \tkzDefLine[parallel=through C](D,B)  \tkzGetPoint{p}
    \tkzInterLL(A,B)(C,p)  \tkzGetPoint{C'}
    \tkzLabelPoints[below](C')
    \tkzDrawSegments[dashed](C,C')

    % 3
    \tkzDrawSegments(D,C')
\end{tikzpicture}

